I find most times you want the site  listed in your Portal Sites Directory anyway, so I generally go there to add any new sites, or to link-up any existing sites. When you use that interface you can chose multiple areas where you want listings created for the site.

You can create  a listing  to point to any Web URL, including the root  of
a WSS Site. Navigate to the Area where you want the listing, click
Manage Content from Actions in the left nav, click Portal Listings,
click Add Listing from the toolbar. Note that you can even put this link
on more than one Area.